Fix typos found in README.md and CONTRIBUTING.MD

[mepv]

Issue description

There are a couple of typos in README.md and CONTRIBUTING.MD files.

README.md 5-0-functional-programming

ablte

- At the end of this module you will be ablte to
+ At the end of this module you will be able to

to uderstnad way

- process data collections in a concise and easy to uderstnad way using Stream API
+ process data collections in a concise and easy way to understand using Stream API

CONTRIBUTING.MD

brnach

- 7. Merge your exercise branch into the solution brnach
+ 7. Merge your exercise branch into the solution branch